Said arrangement comprises at least two image-generating elements which are controllable using a control unit and which enable generation of a partial color image of the multi-color image, and a color combiner arranged following the image-generating elements, wherein the light for the corresponding partial color image coming from the image-generating elements is guided, in one partial beam path each, to the color combiner, which superimposes the light guided in the partial beam paths and emits it as a common beam, said arrangement further comprising projection optics arranged following the color combiner, on which projection optics the common beam impinges and which project the muilticolor image onto the projection surface, and the image scales given by said arrangement being different for two or more partial color images.
In such arrangements for projecting a multi-color image, there is a need to correct the chromatic aberration of magnification of the projection optics (the different image scales), which causes the differently colored components of a pixel, which is to be represented on the projection surface, not to overlie each other. In conventional objective lenses, the chromatic aberration of magnification is corrected by combining optical glasses differing in dispersion (e.g. optical crown/optical flint), and for higher requirements, use may be made of expensive special media having a specific partial dispersion. However, in an arrangement for projecting a multi-color image of the above-mentioned type, correction of the chromatic aberration of magnification is made more difficult, on the one hand, because the color combiner requires a telecentric beam path for the projection light, as the color combiner would otherwise not function sufficiently well, and, on the other hand, because the intercept distance of the projection optics is substantially increased due to the color combiner arranged between the image-generating elements and the projection optics. This leads to more complex and, thus, more expensive projection optics, with the required narrow tolerancing of the dispersion of the employed optical glasses, in particular, leading to a further increased cost.
In view of the above, it is the object of the present invention to improve an arrangement for projection of the aforementioned type in a manner allowing adjustment of the different image scales of the partial color images to each other with minimum effort.